A Review of the Current Understanding on Immune Cell Sensitivity to Variation in Energy Availability
This study takes a broad look into the existing research on the relationship between two physiological topics, nutrition and immunity in vertebrates, specifically the mammalian and avian branches. This was achieved by critiquing available studies on different types of immune cells, and how variable energy availability, as well as specific pathogens, impact cell function. Notably, most studies examined individuals with compromised immune systems, which reveals an existing knowledge gap in the linkages between nutrition and immunity in healthy organisms. Links between immunity and nutrition were identified across the studies, with the three main energy molecules, carbohydrates, lipids, and proteins, implicated in functional roles as immune modulators. Stimulatory and inhibitory effects occur dependent on elevated and depleted nutrient levels, and multiple cell types are sensitive to changes in nutrient availability. Further studies should be conducted on healthy individuals of model species, as well as wildlife and other non-model species to identify and describe the effects of host nutritional status on the spread of pathogens and the implications at the population level for humans, domestic animals, and wildlife.